Project Summary/Abstract The goal of this proposal is to fabricate and test a novel, fully integrated, volumetric high-density microelectrode array and ribbon cable assembly, and the means to surgically deploy this array in sub- cortical target tissue within the brain. Devices based on our indwelling, volumetric multi-electrode arrays and their delivery vehicles would improve treatment options for a myriad of deep brain stimulation (DBS) applications, and have the potential to make a significant impact in neurosurgical applications. DBS is a fast developing field of medicine, which has been shown to have efficacy in treatment of conditions including Parkinson?s Disease, severe depression, morbid obesity, and obsessive compulsive disorder. Current DBS electrodes are typically relatively large in diameter and have low stimulation specificity, with only small numbers of electrodes being able to be implanted into sub-cortical, deep brain structures. The team at Bionic Eye Technologies, in collaboration with researchers at Harvard Medical School, Massachusetts General Hospital and Cornell University, have developed advanced microfabrication processes that enable the manufacture of smaller, controlled stress, splaying volumetric microelectrode arrays outlined below, and this proposal concerns fabrication and testing of an improved version of our pilot arrays that integrates the ribbon cable containing the insulated leads with the microelectrode arrays themselves. This project will result in superior electrode arrays for use in DBS stimulation, improving the surgical outcomes and quality of life for patients with many neurological conditions.